// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef NET_QUIC_QUIC_PACKET_WRITER_H_
#define NET_QUIC_QUIC_PACKET_WRITER_H_

#include <stddef.h>

#include "net/base/ip_endpoint.h"
#include "net/quic/quic_protocol.h"

namespace net {

class IPAddress;
struct WriteResult;

class NET_EXPORT_PRIVATE PerPacketOptions {
public:
    PerPacketOptions() = default;
    virtual ~PerPacketOptions() { }

    // Returns a heap-allocated copy of |this|.
    virtual PerPacketOptions* Clone() const = 0;

private:
    PerPacketOptions(PerPacketOptions&& other) = delete;
    PerPacketOptions& operator=(PerPacketOptions&& other) = delete;

    DISALLOW_COPY_AND_ASSIGN(PerPacketOptions);
};

// An interface between writers and the entity managing the
// socket (in our case the QuicDispatcher).  This allows the Dispatcher to
// control writes, and manage any writers who end up write blocked.
class NET_EXPORT_PRIVATE QuicPacketWriter {
public:
    virtual ~QuicPacketWriter() { }

    // Sends the packet out to the peer, with some optional per-packet options.
    // If the write succeeded, the result's status is WRITE_STATUS_OK and
    // bytes_written is populated. If the write failed, the result's status is
    // WRITE_STATUS_BLOCKED or WRITE_STATUS_ERROR and error_code is populated.
    // Options must be either null, or created for the particular QuicPacketWriter
    // implementation. Options may be ignored, depending on the implementation.
    virtual WriteResult WritePacket(const char* buffer,
        size_t buf_len,
        const IPAddress& self_address,
        const IPEndPoint& peer_address,
        PerPacketOptions* options)
        = 0;

    // Returns true if the writer buffers and subsequently rewrites data
    // when an attempt to write results in the underlying socket becoming
    // write blocked.
    virtual bool IsWriteBlockedDataBuffered() const = 0;

    // Returns true if the network socket is not writable.
    virtual bool IsWriteBlocked() const = 0;

    // Records that the socket has become writable, for example when an EPOLLOUT
    // is received or an asynchronous write completes.
    virtual void SetWritable() = 0;

    // Returns the maximum size of the packet which can be written using this
    // writer for the supplied peer address.  This size may actually exceed the
    // size of a valid QUIC packet.
    virtual QuicByteCount GetMaxPacketSize(
        const IPEndPoint& peer_address) const = 0;
};

} // namespace net

#endif // NET_QUIC_QUIC_PACKET_WRITER_H_
